Traditionally, color pigments and pearl pigments, wherein a plate particle of layered-silicate and the like is used as the base and a metal oxide such as iron oxide is coated on its surface, have been known.
For example, in patent literature 1, low-gloss black iron oxide coated black flake pigments, wherein a mica flake was used as the base of the iron-containing pigment, black iron oxide (Fe3O4) was used as the iron oxide that was coated on the surface, and the Fe3O4 was deposited on a muscovite particle itself or a muscovite particle coated with TiO2 and ZrO2, are described.
In addition, it is described in patent literature 2 that a nacreous pigment with a coating layer of Fe3O4 and having an interference color can be obtained by coating a platelet-shaped substrate such as mica with a smooth iron(III) oxide layer, wherein very fine crystals are uniformly and densely packed, and converting this to a layer containing iron(II) oxide by exposing to a reducing atmosphere at 100° C. or higher.
In patent literature 3, a black bright pigment wherein the surface portion of a flaky glass base is coated with a thin film, with a thickness of 10 nm to 1 μm, of Fe3O4 and/or a low-order titanium oxide is mentioned. It is described that a pigment excellent in brightness can be obtained by using flaky glass as the base because of its high surface smoothness. It is also described that if the thickness of the coating layer exceeds 300 nm, the interference color becomes weak, the development of black color becomes strong, and the concealment rate also becomes high.
However, in these conventional iron oxide-coated layered silicate pigments, gloss is low when blackness is satisfactory. On the other hand, when gloss is satisfactory, an interference color develops in addition to a black color. Accordingly, they were not entirely satisfactory in the blackness inherent in black iron oxide and in the gloss inherent in plate particles. That is, there have been no iron oxide-coated layered silicate pigments that can sufficiently satisfy both the iron oxide-inherent color and gloss.